Add Patrol docs to integration test

[pdenert]

New file created

• /testing/patrol-tests/index.md — Full "Write and run a Patrol test" guide covering setup, writing tests with patrolTest and $ finders, running with patrol test / patrol develop, and platform interactions via $.platform API. Links to Patrol docs for native side integration and app initialization details.

Files modified

• /testing/overview.md (Integration tests section)

  • Added paragraph noting integration_test can't interact with native platform UI, and introducing Patrol as the alternative
  • Changed "integration testing page" link to point to /cookbook/testing/integration/introduction
  • Added "Write and run a Patrol test" recipe link

• /cookbook/testing/integration/introduction.md (Integration testing concepts)

  • Restructured into a "Testing frameworks" section presenting integration_test and Patrol side by side
  • Added Patrol subsection with capabilities (native UI, device features, custom finders)
  • Renamed "Dependent package" to "Getting started" with setup links for both frameworks

• /testing/testing-plugins.md (Testing plugins)

  • Added Patrol as a separate bullet point under "Types of plugin tests"
  • Updated "native UI tests" paragraph to mention Patrol as a Dart-based alternative to Espresso/XCUITest
  • Updated "What types of tests to add" section to recommend Patrol for native UI flows

• sidenav/default.yml

  • Added "Write and run a Patrol test" entry under Integration testing

  To test it:

  • clone this repo
  • switch to "patrol" branch
  • dart run dash_site serve
  • go to: http://localhost:8080/

Presubmit checklist

• If you are unwilling, or unable, to sign the CLA, even for a tiny, one-word PR, please file an issue instead of a PR.
• If this PR is not meant to land until a future stable release, mark it as draft with an explanation.
• This PR follows the Google Developer Documentation Style Guidelines—for example, it doesn't use i.e. or e.g., and it avoids I and we (first-person pronouns).
• This PR uses semantic line breaks
  of 80 characters or fewer.